Natural electoral selection

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IN 1936, a Russian biologist put two simple organisms into a test tube to see what would happen. He discovered that one always drove the other into extinction. The one with the slightest advantage took over more and more of the food. The other one died out. The experiments gave birth to a seminal theory in biology: that rivals competing over a finite resource cannot coexist.

I have been thinking a lot about those simple organisms as I watch the Republicans and wonder: How can so many candidates stay in the race? Why can’t one of them just get the upper hand and win?

So I called up Marc Feldman, a Stanford professor who studies competition in the natural world. His advice? “Look at lizards in the Caribbean,’’ Feldman said.

Animals with formidable rivals, he explained, avoid extinction by carving out a niche. Some lizard species live in tree roots. Others live in the leaves. Still others live in the bark of the trees’ midsection. Instead of fighting over the entire tree - and risking extinction - the lizards master a tiny area where they have a tiny advantage. Over time, they evolve to become perfectly suited for hunting insects in their niche.

You could say the same about politics. Each Republican candidate has survived by carving out a specific part of the Republican electorate. For Romney, it’s the business community. For Rick Santorum, it’s the social conservatives. For Ron Paul, it’s the libertarian strand. Newt Gingrich hasn’t quite found his niche, and his campaign is floundering. The only reason he hasn’t gone extinct is that a friendly donor feeds him and keeps him alive.

Each one of them would like to dominate the entire Republican electorate - just like the lizards would like to dominate the entire tree. But competitors make it impossible. A root lizard that goes hunting in the leaves will never be able to do as well as the leaf lizards there. Similarly, a candidate who goes after voters outside his niche will constantly be defeated by the rival who has already cultivated those voters.

Mother Nature allows lizards to survive on the same tree until the end of time. But mercifully, the Republican race will one day come to an end. Once there is a winner and the rivals disappear, won’t all that competition make the nominee better equipped to beat Obama? “Not so much,’’ Feldman said. Competition doesn’t necessarily make us stronger. It only makes us more specialized.

The very adaptations that make a lizard thrive on a specific part of a specific tree handicap it against a different rival in a different environment. That’s also true in politics: the tough stance on birth control that wins the Republican race handicaps a candidate in the general election.

“It’s pretty well known in ecology that if you have one kind of organism - for instance, bacteria - competing against others in a petri dish, it might win that competition, but when you put it into a new environment, there is no guarantee that it will do at all well,’’ Feldman said. “And if you put it in another dish to compete with bacteria that has already adapted to that second dish, it loses.’’

In other words, while the Republicans have been duking it out in their own dish, Obama has focused on the general election - the second petri dish. He is already adapted.

But presidential candidates are not bacteria, and elections are not petri dishes. Sure that the analogy’s usefulness had come to its end, I thanked Feldman and started to hang up the phone.

Not so fast, Feldman told me. There is one more important thing I needed to understand: the idea behind “Niche Construction,’’ a revolutionary book that he coauthored in 2003.

“Darwin thought animals were adapting to an environment that was static,’’ Feldman said. But in reality, it is constantly changing in response to the creatures themselves. Animals can change their ecosystems in ways that hurt their future chances of survival. A lizard that gets too good at catching beetles depletes that food source for the next generation.

Which candidates face extinction? Look to lizards for the answer.

It’s a cautionary tale for Republican candidates: Beware of adopting views so extreme that you alter the ecology - that is, by driving a lot of voters away. Beware of becoming such a master of your own tiny domain that you won’t be able survive anywhere else.

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